Watermarking of the multimedia contents is of prime importance for claiming and establishing ownership. An image watermark is data added to the image data. This added data is included in such a way that the image quality is not degraded. Later extraction tools may be applied to the image data to recover the watermark. The recovered watermark is evidence of the original ownership claim to the image.
Most of watermarking techniques are vulnerable to the attacks or are poorly extracted after the attacks. Images are very common in multimedia contents and need a robust watermarking scheme that can withstand the attacks and at the same time have a recognizable extracted watermark.
In recent years, image watermarking has been a very active area of research and industry. Various techniques have been used for image watermarking in the spatial domain, the transform domain and the spread spectrum domain.